# std::feraiseexcept

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< cpp‎ | numeric‎ | fenv

Defined in header `<cfenv>` |  |
int feraiseexcept( int excepts ); |  | (since C++11)

Attempts to raise all floating point exceptions listed in `excepts` (a bitwise OR of the floating point exception macros). If one of the exceptions is FE_OVERFLOW or FE_UNDERFLOW, this function may additionally raise FE_INEXACT. The order in which the exceptions are raised is unspecified, except that FE_OVERFLOW and FE_UNDERFLOW are always raised before FE_INEXACT.

### Parameters

excepts | - | bitmask listing the exception flags to raise

### Return value

​0​ if all listed exceptions were raised, non-zero value otherwise.

### Example

Run this code

    #include <cfenv>
    #include <iostream>

    // #pragma STDC FENV_ACCESS ON

    int main()
    {
        std::feclearexcept(FE_ALL_EXCEPT);
        const int r = std::feraiseexcept(FE_UNDERFLOW | FE_DIVBYZERO);
        std::cout << "Raising divbyzero and underflow simultaneously "
                  << (r ? "fails" : "succeeds") << " and results in\n";

        const int e = std::fetestexcept(FE_ALL_EXCEPT);
        if (e & FE_DIVBYZERO)
            std::cout << "division by zero\n";
        if (e & FE_INEXACT)
            std::cout << "inexact\n";
        if (e & FE_INVALID)
            std::cout << "invalid\n";
        if (e & FE_UNDERFLOW)
            std::cout << "underflow\n";
        if (e & FE_OVERFLOW)
            std::cout << "overflow\n";
    }

Output:

    Raising divbyzero and underflow simultaneously succeeds and results in
    division by zero
    underflow

### See also

feclearexcept (C++11) | clears the specified floating-point status flags (function)
fetestexcept (C++11) | determines which of the specified floating-point status flags are set (function)
C documentation for feraiseexcept

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